Henrietta Lacks was born more than 97 years ago in South Virginia. This tobacco grower, who died from cervical cancer in 1951 at the age of 31, contributed to one of the biggest medical discoveries in history: in short, a part of her lived on for 66 years after her death, in the form of cells used in research throughout the entire world. An unexpected discovery In 1951, Lacks went into Johns Hopkins hospital for surgery on a rapidly growing tumor. At the time, this hospital was the only one in the area that would treat African-American patients and during the operation, the surgeon removed a bit of Henrietta’s tumor without informing her about it. In the 1950s, researchers tried desperately to keep these human cells alive for experimental purposes. Henrietta’s surgeon gave the piece of tissue to a specialist who saw that these cells had an incredible power. Whilst her cells would have divided around 40 times on average throughout her short life, Henrietta’s cells continued to divide indefinitely without any sign of slowing down. That is how they became the very first cell lining: a group of cells which were possible to grow and preserve indefinitely. Experiments could then be performed on this cell lining without having to take samples from a living human being. In the case of Lacks, this was due to a natural mutation that we will explain later on, whilst other cell linings are artificially created in a lab. Nowadays, Lack’s cells (named HeLa) continue to develop even more than 66 years afterwards. More than 50 million tons have been produced, which is enough to stretch around the world three times. These cells have allowed generations of scientists to do numerous experiments on living cells. Although they were cancerous and genetically different from typical human cells, these HeLa cells behaved like normal cells in many ways. They are therefore very useful to use to study bacteria, hormones and in particular, viruses. A priceless heritage Since the beginning of the 20th century, researchers have followed each other in attempting to find a vaccine for polio. Numerous studies have been carried out on rhesus monkeys, but it quickly became difficult to obtain enough specimens. However, thanks to the HeLa cells, Jonas Salk managed to design a vaccine in the 50s, which, after some perfecting, will contribute to a drastic reduction in the number of polio cases in the world. The HeLa cells have been referred to in tens of thousands of articles and used on countless occasions, for researching treatments against Parkinson’s disease, herpes or some cancers for the study of cloning, genetics and the effect of radiation. However, until recently, nobody has been able to explain how these cells were able to continue to divide uncontrollably. It was only in 2013 that a team at the University of Washington found an answer. In their study published in the Nature journal, researchers showed that a part of the genome of the HPV virus linked to cancer was also linked to Henrietta’s. The virus, which contained its own cancerogenic genes, matched Lack’s cancerogenic genes (these genes mutate into cancer if they are modified). The proximity of these genes then led them to be stimulated at the same time and boost the effects, triggering this unrestrained multiplication in Henrietta’s cells. The use of Lack’s cells has been controversial over the years. Consent for this extraction was not given by Henrietta at the time, and her family were never consulted about using these cells. Numerous pseudonyms had been given to the patient to hide her identity, but when it was revealed in the 70s, her close family obtained a right of scrutiny for the production of future research during this long-term struggle.